code: def test_subcommand_not_found():
      with pytest.raises(CalledProcessError) as excinfo:
          get_jupyter_output("nonexistant-subcommand")
      stderr = excinfo.value.stderr.decode("utf8")
      assert (
          "Jupyter command `jupyter-nonexistant-subcommand` not found."
          in stderr
      )
  
imports: from __future__ import annotations
  import json
  import os
  import sys
  import sysconfig
  from subprocess import PIPE, CalledProcessError, check_output
  from unittest.mock import patch
  import pytest
  from jupyter_core import __version__
  from jupyter_core.command import list_subcommands
  from jupyter_core.paths import jupyter_config_dir, jupyter_config_path, jupyter_data_dir, jupyter_path, jupyter_runtime_dir
label_desc: Use image node_id 14 for calling a global function with example usage: test_subcommand_not_found() without return types